text: First, a thin section of the sample is cut, often using a microtome. Various other stages of sample preparation may then take place.
  The prepared sample is then incubated with a specific antibody designed to bind the molecule of interest. Next, a secondary antibody which has gold particles attached is added, and it binds to the primary antibody. Gold can also be attached to protein A or protein G instead of a secondary antibody, as these proteins bind mammalian IgG Fc regions in a non-specific way.
  The electron-dense gold particle can now be seen under an electron microscope as a black dot, indirectly labeling the molecule of interest.